1 #ifndef _LINUX_MODULE_PARAMS_H 2 #define _LINUX_MODULE_PARAMS_H 3 /* (C) Copyright 2001, 2002 Rusty Russell IBM Corporation */ 4 #include <linux/init.h> 5 #include <linux/stringify.h> 6 #include <linux/kernel.h> 7 8 /* You can override this manually, but generally this should match the 9 module name. */ 10 #ifdef MODULE 11 #define MODULE_PARAM_PREFIX /* empty */ 12 #else 13 #define MODULE_PARAM_PREFIX KBUILD_MODNAME "." 14 #endif 15 16 /* Chosen so that structs with an unsigned long line up. */ 17 #define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long)) 18 19 #define ___module_cat(a,b) __mod_ ## a ## b 20 #define __module_cat(a,b) ___module_cat(a,b) 21 #ifdef MODULE 22 #define __MODULE_INFO(tag, name, info) \ 23 static const char __module_cat(name,__LINE__)[] \ 24 __used __attribute__((section(".modinfo"), unused, aligned(1))) \ 25 = __stringify(tag) "=" info 26 #else /* !MODULE */ 27 /* This struct is here for syntactic coherency, it is not used */ 28 #define __MODULE_INFO(tag, name, info) \ 29 struct __module_cat(name,__LINE__) {} 30 #endif 31 #define __MODULE_PARM_TYPE(name, _type) \ 32 __MODULE_INFO(parmtype, name##type, #name ":" _type) 33 34 /* One for each parameter, describing how to use it. Some files do 35 multiple of these per line, so can't just use MODULE_INFO. */ 36 #define MODULE_PARM_DESC(_parm, desc) \ 37 __MODULE_INFO(parm, _parm, #_parm ":" desc) 38 39 struct kernel_param; 40 41 struct kernel_param_ops { 42 /* Returns 0, or -errno. arg is in kp->arg. */ 43 int (*set)(const char *val, const struct kernel_param *kp); 44 /* Returns length written or -errno. Buffer is 4k (ie. be short!) */ 45 int (*get)(char *buffer, const struct kernel_param *kp); 46 /* Optional function to free kp->arg when module unloaded. */ 47 void (*free)(void *arg); 48 }; 49 50 struct kernel_param { 51 const char *name; 52 const struct kernel_param_ops *ops; 53 u16 perm; 54 s16 level; 55 union { 56 void *arg; 57 const struct kparam_string *str; 58 const struct kparam_array *arr; 59 }; 60 }; 61 62 /* Special one for strings we want to copy into */ 63 struct kparam_string { 64 unsigned int maxlen; 65 char *string; 66 }; 67 68 /* Special one for arrays */ 69 struct kparam_array 70 { 71 unsigned int max; 72 unsigned int elemsize; 73 unsigned int *num; 74 const struct kernel_param_ops *ops; 75 void *elem; 76 }; 77 78 /** 79 * module_param - typesafe helper for a module/cmdline parameter 80 * @value: the variable to alter, and exposed parameter name. 81 * @type: the type of the parameter 82 * @perm: visibility in sysfs. 83 * 84 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a 85 * ".") the kernel commandline parameter. Note that - is changed to _, so 86 * the user can use "foo-bar=1" even for variable "foo_bar". 87 * 88 * @perm is 0 if the the variable is not to appear in sysfs, or 0444 89 * for world-readable, 0644 for root-writable, etc. Note that if it 90 * is writable, you may need to use kparam_block_sysfs_write() around 91 * accesses (esp. charp, which can be kfreed when it changes). 92 * 93 * The @type is simply pasted to refer to a param_ops_##type and a 94 * param_check_##type: for convenience many standard types are provided but 95 * you can create your own by defining those variables. 96 * 97 * Standard types are: 98 * byte, short, ushort, int, uint, long, ulong 99 * charp: a character pointer 100 * bool: a bool, values 0/1, y/n, Y/N. 101 * invbool: the above, only sense-reversed (N = true). 102 */ 103 #define module_param(name, type, perm) \ 104 module_param_named(name, name, type, perm) 105 106 /** 107 * module_param_named - typesafe helper for a renamed module/cmdline parameter 108 * @name: a valid C identifier which is the parameter name. 109 * @value: the actual lvalue to alter. 110 * @type: the type of the parameter 111 * @perm: visibility in sysfs. 112 * 113 * Usually it's a good idea to have variable names and user-exposed names the 114 * same, but that's harder if the variable must be non-static or is inside a 115 * structure. This allows exposure under a different name. 116 */ 117 #define module_param_named(name, value, type, perm) \ 118 param_check_##type(name, &(value)); \ 119 module_param_cb(name, ¶m_ops_##type, &value, perm); \ 120 __MODULE_PARM_TYPE(name, #type) 121 122 /** 123 * module_param_cb - general callback for a module/cmdline parameter 124 * @name: a valid C identifier which is the parameter name. 125 * @ops: the set & get operations for this parameter. 126 * @perm: visibility in sysfs. 127 * 128 * The ops can have NULL set or get functions. 129 */ 130 #define module_param_cb(name, ops, arg, perm) \ 131 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1) 132 133 /** 134 * <level>_param_cb - general callback for a module/cmdline parameter 135 * to be evaluated before certain initcall level 136 * @name: a valid C identifier which is the parameter name. 137 * @ops: the set & get operations for this parameter. 138 * @perm: visibility in sysfs. 139 * 140 * The ops can have NULL set or get functions. 141 */ 142 #define __level_param_cb(name, ops, arg, perm, level) \ 143 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level) 144 145 #define core_param_cb(name, ops, arg, perm) \ 146 __level_param_cb(name, ops, arg, perm, 1) 147 148 #define postcore_param_cb(name, ops, arg, perm) \ 149 __level_param_cb(name, ops, arg, perm, 2) 150 151 #define arch_param_cb(name, ops, arg, perm) \ 152 __level_param_cb(name, ops, arg, perm, 3) 153 154 #define subsys_param_cb(name, ops, arg, perm) \ 155 __level_param_cb(name, ops, arg, perm, 4) 156 157 #define fs_param_cb(name, ops, arg, perm) \ 158 __level_param_cb(name, ops, arg, perm, 5) 159 160 #define device_param_cb(name, ops, arg, perm) \ 161 __level_param_cb(name, ops, arg, perm, 6) 162 163 #define late_param_cb(name, ops, arg, perm) \ 164 __level_param_cb(name, ops, arg, perm, 7) 165 166 /* On alpha, ia64 and ppc64 relocations to global data cannot go into 167 read-only sections (which is part of respective UNIX ABI on these 168 platforms). So 'const' makes no sense and even causes compile failures 169 with some compilers. */ 170 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64) 171 #define __moduleparam_const 172 #else 173 #define __moduleparam_const const 174 #endif 175 176 /* This is the fundamental function for registering boot/module 177 parameters. */ 178 #define __module_param_call(prefix, name, ops, arg, perm, level) \ 179 /* Default value instead of permissions? */ \ 180 static int __param_perm_check_##name __attribute__((unused)) = \ 181 BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)) \ 182 + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN); \ 183 static const char __param_str_##name[] = prefix #name; \ 184 static struct kernel_param __moduleparam_const __param_##name \ 185 __used \ 186 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \ 187 = { __param_str_##name, ops, perm, level, { arg } } 188 189 /* Obsolete - use module_param_cb() */ 190 #define module_param_call(name, set, get, arg, perm) \ 191 static struct kernel_param_ops __param_ops_##name = \ 192 { (void *)set, (void *)get }; \ 193 __module_param_call(MODULE_PARAM_PREFIX, \ 194 name, &__param_ops_##name, arg, \ 195 (perm) + sizeof(__check_old_set_param(set))*0, -1) 196 197 /* We don't get oldget: it's often a new-style param_get_uint, etc. */ 198 static inline int 199 __check_old_set_param(int (*oldset)(const char *, struct kernel_param *)) 200 { 201 return 0; 202 } 203 204 /** 205 * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs. 206 * @name: the name of the parameter 207 * 208 * There's no point blocking write on a paramter that isn't writable via sysfs! 209 */ 210 #define kparam_block_sysfs_write(name) \ 211 do { \ 212 BUG_ON(!(__param_##name.perm & 0222)); \ 213 __kernel_param_lock(); \ 214 } while (0) 215 216 /** 217 * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again. 218 * @name: the name of the parameter 219 */ 220 #define kparam_unblock_sysfs_write(name) \ 221 do { \ 222 BUG_ON(!(__param_##name.perm & 0222)); \ 223 __kernel_param_unlock(); \ 224 } while (0) 225 226 /** 227 * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs. 228 * @name: the name of the parameter 229 * 230 * This also blocks sysfs writes. 231 */ 232 #define kparam_block_sysfs_read(name) \ 233 do { \ 234 BUG_ON(!(__param_##name.perm & 0444)); \ 235 __kernel_param_lock(); \ 236 } while (0) 237 238 /** 239 * kparam_unblock_sysfs_read - allows sysfs to read a parameter again. 240 * @name: the name of the parameter 241 */ 242 #define kparam_unblock_sysfs_read(name) \ 243 do { \ 244 BUG_ON(!(__param_##name.perm & 0444)); \ 245 __kernel_param_unlock(); \ 246 } while (0) 247 248 #ifdef CONFIG_SYSFS 249 extern void __kernel_param_lock(void); 250 extern void __kernel_param_unlock(void); 251 #else 252 static inline void __kernel_param_lock(void) 253 { 254 } 255 static inline void __kernel_param_unlock(void) 256 { 257 } 258 #endif 259 260 #ifndef MODULE 261 /** 262 * core_param - define a historical core kernel parameter. 263 * @name: the name of the cmdline and sysfs parameter (often the same as var) 264 * @var: the variable 265 * @type: the type of the parameter 266 * @perm: visibility in sysfs 267 * 268 * core_param is just like module_param(), but cannot be modular and 269 * doesn't add a prefix (such as "printk."). This is for compatibility 270 * with __setup(), and it makes sense as truly core parameters aren't 271 * tied to the particular file they're in. 272 */ 273 #define core_param(name, var, type, perm) \ 274 param_check_##type(name, &(var)); \ 275 __module_param_call("", name, ¶m_ops_##type, &var, perm, -1) 276 #endif /* !MODULE */ 277 278 /** 279 * module_param_string - a char array parameter 280 * @name: the name of the parameter 281 * @string: the string variable 282 * @len: the maximum length of the string, incl. terminator 283 * @perm: visibility in sysfs. 284 * 285 * This actually copies the string when it's set (unlike type charp). 286 * @len is usually just sizeof(string). 287 */ 288 #define module_param_string(name, string, len, perm) \ 289 static const struct kparam_string __param_string_##name \ 290 = { len, string }; \ 291 __module_param_call(MODULE_PARAM_PREFIX, name, \ 292 ¶m_ops_string, \ 293 .str = &__param_string_##name, perm, -1); \ 294 __MODULE_PARM_TYPE(name, "string") 295 296 /** 297 * parameq - checks if two parameter names match 298 * @name1: parameter name 1 299 * @name2: parameter name 2 300 * 301 * Returns true if the two parameter names are equal. 302 * Dashes (-) are considered equal to underscores (_). 303 */ 304 extern bool parameq(const char *name1, const char *name2); 305 306 /** 307 * parameqn - checks if two parameter names match 308 * @name1: parameter name 1 309 * @name2: parameter name 2 310 * @n: the length to compare 311 * 312 * Similar to parameq(), except it compares @n characters. 313 */ 314 extern bool parameqn(const char *name1, const char *name2, size_t n); 315 316 /* Called on module insert or kernel boot */ 317 extern int parse_args(const char *name, 318 char *args, 319 const struct kernel_param *params, 320 unsigned num, 321 s16 level_min, 322 s16 level_max, 323 int (*unknown)(char *param, char *val, 324 const char *doing)); 325 326 /* Called by module remove. */ 327 #ifdef CONFIG_SYSFS 328 extern void destroy_params(const struct kernel_param *params, unsigned num); 329 #else 330 static inline void destroy_params(const struct kernel_param *params, 331 unsigned num) 332 { 333 } 334 #endif /* !CONFIG_SYSFS */ 335 336 /* All the helper functions */ 337 /* The macros to do compile-time type checking stolen from Jakub 338 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */ 339 #define __param_check(name, p, type) \ 340 static inline type *__check_##name(void) { return(p); } 341 342 extern struct kernel_param_ops param_ops_byte; 343 extern int param_set_byte(const char *val, const struct kernel_param *kp); 344 extern int param_get_byte(char *buffer, const struct kernel_param *kp); 345 #define param_check_byte(name, p) __param_check(name, p, unsigned char) 346 347 extern struct kernel_param_ops param_ops_short; 348 extern int param_set_short(const char *val, const struct kernel_param *kp); 349 extern int param_get_short(char *buffer, const struct kernel_param *kp); 350 #define param_check_short(name, p) __param_check(name, p, short) 351 352 extern struct kernel_param_ops param_ops_ushort; 353 extern int param_set_ushort(const char *val, const struct kernel_param *kp); 354 extern int param_get_ushort(char *buffer, const struct kernel_param *kp); 355 #define param_check_ushort(name, p) __param_check(name, p, unsigned short) 356 357 extern struct kernel_param_ops param_ops_int; 358 extern int param_set_int(const char *val, const struct kernel_param *kp); 359 extern int param_get_int(char *buffer, const struct kernel_param *kp); 360 #define param_check_int(name, p) __param_check(name, p, int) 361 362 extern struct kernel_param_ops param_ops_uint; 363 extern int param_set_uint(const char *val, const struct kernel_param *kp); 364 extern int param_get_uint(char *buffer, const struct kernel_param *kp); 365 #define param_check_uint(name, p) __param_check(name, p, unsigned int) 366 367 extern struct kernel_param_ops param_ops_long; 368 extern int param_set_long(const char *val, const struct kernel_param *kp); 369 extern int param_get_long(char *buffer, const struct kernel_param *kp); 370 #define param_check_long(name, p) __param_check(name, p, long) 371 372 extern struct kernel_param_ops param_ops_ulong; 373 extern int param_set_ulong(const char *val, const struct kernel_param *kp); 374 extern int param_get_ulong(char *buffer, const struct kernel_param *kp); 375 #define param_check_ulong(name, p) __param_check(name, p, unsigned long) 376 377 extern struct kernel_param_ops param_ops_charp; 378 extern int param_set_charp(const char *val, const struct kernel_param *kp); 379 extern int param_get_charp(char *buffer, const struct kernel_param *kp); 380 #define param_check_charp(name, p) __param_check(name, p, char *) 381 382 /* We used to allow int as well as bool. We're taking that away! */ 383 extern struct kernel_param_ops param_ops_bool; 384 extern int param_set_bool(const char *val, const struct kernel_param *kp); 385 extern int param_get_bool(char *buffer, const struct kernel_param *kp); 386 #define param_check_bool(name, p) __param_check(name, p, bool) 387 388 extern struct kernel_param_ops param_ops_invbool; 389 extern int param_set_invbool(const char *val, const struct kernel_param *kp); 390 extern int param_get_invbool(char *buffer, const struct kernel_param *kp); 391 #define param_check_invbool(name, p) __param_check(name, p, bool) 392 393 /* An int, which can only be set like a bool (though it shows as an int). */ 394 extern struct kernel_param_ops param_ops_bint; 395 extern int param_set_bint(const char *val, const struct kernel_param *kp); 396 #define param_get_bint param_get_int 397 #define param_check_bint param_check_int 398 399 /** 400 * module_param_array - a parameter which is an array of some type 401 * @name: the name of the array variable 402 * @type: the type, as per module_param() 403 * @nump: optional pointer filled in with the number written 404 * @perm: visibility in sysfs 405 * 406 * Input and output are as comma-separated values. Commas inside values 407 * don't work properly (eg. an array of charp). 408 * 409 * ARRAY_SIZE(@name) is used to determine the number of elements in the 410 * array, so the definition must be visible. 411 */ 412 #define module_param_array(name, type, nump, perm) \ 413 module_param_array_named(name, name, type, nump, perm) 414 415 /** 416 * module_param_array_named - renamed parameter which is an array of some type 417 * @name: a valid C identifier which is the parameter name 418 * @array: the name of the array variable 419 * @type: the type, as per module_param() 420 * @nump: optional pointer filled in with the number written 421 * @perm: visibility in sysfs 422 * 423 * This exposes a different name than the actual variable name. See 424 * module_param_named() for why this might be necessary. 425 */ 426 #define module_param_array_named(name, array, type, nump, perm) \ 427 param_check_##type(name, &(array)[0]); \ 428 static const struct kparam_array __param_arr_##name \ 429 = { .max = ARRAY_SIZE(array), .num = nump, \ 430 .ops = ¶m_ops_##type, \ 431 .elemsize = sizeof(array[0]), .elem = array }; \ 432 __module_param_call(MODULE_PARAM_PREFIX, name, \ 433 ¶m_array_ops, \ 434 .arr = &__param_arr_##name, \ 435 perm, -1); \ 436 __MODULE_PARM_TYPE(name, "array of " #type) 437 438 extern struct kernel_param_ops param_array_ops; 439 440 extern struct kernel_param_ops param_ops_string; 441 extern int param_set_copystring(const char *val, const struct kernel_param *); 442 extern int param_get_string(char *buffer, const struct kernel_param *kp); 443 444 /* for exporting parameters in /sys/parameters */ 445 446 struct module; 447 448 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES) 449 extern int module_param_sysfs_setup(struct module *mod, 450 const struct kernel_param *kparam, 451 unsigned int num_params); 452 453 extern void module_param_sysfs_remove(struct module *mod); 454 #else 455 static inline int module_param_sysfs_setup(struct module *mod, 456 const struct kernel_param *kparam, 457 unsigned int num_params) 458 { 459 return 0; 460 } 461 462 static inline void module_param_sysfs_remove(struct module *mod) 463 { } 464 #endif 465 466 #endif /* _LINUX_MODULE_PARAMS_H */ 467